“After the game, he went to the doctors,” Caldwell said. “He was exhibiting some issues, they evaluated him and thus they had to put him in (protocol), which he’s in today. You probably won’t see him out at practice this afternoon.”

This is at least the fourth time a Lions player has entered protocol after a game they finished, including guard T.J. Lang earlier this year. It raises concerns about whether players are doing a sufficient job self-reporting symptoms in the moment.

“It’s hard for me to assess, but we’ve had a couple issues where symptoms have shown up after the game and players came in and talked to the doctors,” Caldwell said. “I think it goes without saying, these days, in terms of the importance of it and those types of those things. Our players are well aware. We go through a complete and thorough introduction before the season starts, before pads are put on, and it’s run by our doctors and also our medical personnel.”

The league’s protocol is under heavy scrutiny this week after Houston quarterback Tom Savage was captured on camera trembling after a big hit on the sidelines. He was quickly assessed by the team’s medical staff and allowed to return to the game the next series, before finally being pulled.

“I think everything evolves,” Caldwell said. “I do think everything gets examined, particularly in that area, constantly in our league. A lot of time and money and effort, in terms of making certain the proper procedures are put in place.”